🏗️ Treadwheel Harbour Crane: Torque, Load, Lifting Speed and Human Power (2D)

Side view of a medieval harbour crane in which workers walk inside a large wheel that turns a drum and winds a rope through a block and tackle. Change the number of workers, the wheel and drum radii, the rope falls, the efficiency and the load, and see the stall limit, the steady lifting speed, the time to lift and the power each worker delivers. The torque balance, the energy bookkeeping, the heaviest load and the mechanical advantage are checked numerically, with four in-page numerical checks.